(1) Technical Field
The present invention relates to techniques for fusing sensor data for object classification. More specifically, the present invention relates to the control of vehicle systems, such as air bag deployment systems, based on the classification of vehicle occupants.
(2) Discussion
Virtually all modern passenger vehicles have air bag deployment systems. The earliest versions of air bag deployment systems provided only front seat driver-side air bag deployment, but later versions included front seat passenger-side deployment. Current deployment systems provide side air bag deployment. Future air bag deployment systems will also include protection for passengers in rear seats. Today's air bag deployment systems are generally triggered whenever there is a significant vehicle impact, and will activate even if the area to be protected is unoccupied or is occupied by someone unlikely to be protected by the air bag.
While thousands of lives have been saved by air bags, a number of people have been injured and a few have been killed by the deploying air bag. Many of these injuries and deaths have been caused by the vehicle occupant being too close to the air bag when it deploys. Children and small adults have been particularly susceptible to injuries from air bags. Also, an infant in a rear-facing infant seat placed on the right front passenger seat is in serious danger of injury if the passenger airbag deploys. The United States Government has recognized this danger and has mandated that car companies provide their customers with the ability to disable the passenger side air bag. Of course, when the air bag is disabled, passengers, including full size adults, are provided with no air bag protection on the passenger side.
Therefore, a need exists for detecting the presence of a vehicle occupant within an area protected by an air bag. Additionally, if an occupant is present, the nature of the occupant must be determined so that air bag deployment can be fashioned so as to eliminate or minimize injury to the occupant.
Various mechanisms have been disclosed for occupant sensing. Breed et al. in U.S. Pat. No. 5,845,000, issued Dec. 1, 1998, describe a system to identify, locate, and monitor occupants in the passenger compartment of a motor vehicle. The system uses electromagnetic sensors to detect and image vehicle occupants. Breed et al. suggest that a trainable pattern recognition technology be used to process the image data to classify the occupants of a vehicle and make decisions as to the deployment of air bags. Breed et al. describe training the pattern recognition system with over one thousand experiments before the system is sufficiently trained to recognize various vehicle occupant states. The system also appears to rely solely upon recognition of static patterns. Such a system, even after training, may be subject to the confusions that can occur between certain occupant types and positions because the richness of the occupant representation is limited. It may produce ambiguous results, for example, when the occupant moves his hand toward the instrument panel.
A sensor fusion approach for vehicle occupancy is disclosed by Corrado, et al. in U.S. Pat. No. 6,026,340, issued Feb. 15, 2000. In Corrado, data from various sensors is combined in a microprocessor to produce a vehicle occupancy state output. Corrado discloses an embodiment where passive thermal signature data and active acoustic distance data are combined and processed to determine various vehicle occupancy states and to determine whether an air bag should be deployed. The system disclosed by Corrado detects and processes motion data as part of its sensor processing, thus providing additional data upon which air bag deployment decisions can be based. However, Corrado discloses multiple sensors to capture the entire passenger volume for the collection of vehicle occupancy data, increasing the complexity and decreasing the reliability of the system. Also, the resolution of the sensors at infrared and ultrasonic frequencies is limited, which increases the possibility that the system may incorrectly detect an occupancy state or require additional time to make an air bag deployment decision.
Accordingly, there exists a need in the art for a fast and reliable system for detection and recognizing occupants in vehicles for use in conjunction with vehicle air bag deployment systems. There is also a need for a system that can meet the aforementioned requirements with a sensor system that is a cost-effective component of the vehicle.